my $sql = 'SELECT SUM(COALESCE(amount,0)) FROM cust_bill_pkg_detail '.
' WHERE billpkgnum = '. $self->billpkgnum;
- $sql .= " AND classnum = $classnum" if defined($classnum);
+ if (defined $classnum) {
+ if ($classnum =~ /^(\d+)$/) {
+ $sql .= " AND classnum = $1";
+ } elsif ($classnum eq '') {
+ $sql .= " AND classnum IS NULL";
+ }
+ }
my $sth = dbh->prepare($sql) or die dbh->errstr;
$sth->execute or die $sth->errstr;